American Sign Language: "smooth"

SMOOTH:
The handshape starts as a "flattened O." Move both hands
forward. The
thumbs start near the pinkie and slide over the fingers. The handshape
becomes an "A-hand" as the hands move forward.

SLICK / smooth:
The thumbprints start touching the prints of the middle fingers. As you move
the hand forward the middle finger bends more and side of the tip of the
middle finger slides down along the thumb.